Fig 4. Uni-strand piRNA clusters produce more piRNAs in the Paris than in the Misy strain.

(A) Scatter plot of log₂-transformed and RPM-normalized small RNA expression in ovaries of Paris and Misy strains. piRNA expression was additionally normalized to the log₂-transformed and RPM-normalized genomic abundance of the corresponding TEs estimated as number of DNA-seq reads mapped to the canonical TE sequences. The color of dots indicates the type of TEs according to its capacity for maternal deposition in embryos according to [24]. Dashed lines depict the results of linear regression analysis for TEs with high maternal deposition (genuine germinal TEs, red) and for TEs with weak maternal deposition (genuine somatic TEs, blue). R²—adjusted squared R (P-value < 0.1). (B) Relative abundance (Paris/Misy) of a normalized number of single-mapped small RNA reads (RPM, 24–29 nt reads were considered) mapping to TE copies located within uni-strand piRNA clusters #8 (flamenco, expressed in follicular cells) and #2 (20A, expressed in the germline).